Multi-Needle Chain-Stitch Sewing Machine

ABSTRACT

The invention relates to a multi-needle chain-stitch sewing machine, for the production of mattress sheets, made from a sewed material, comprising several, in particular at least three sewed material layers, preferably with one sewed material layer made from an elastic material, for example sponge, and a cover layer with a sewing pattern, by means of a sewing machine and a supply device for the sewed material layers to be sewn. According to the invention, a multi-needle chain-stitch sewing machine may be further developed which avoids the problems of conventional solutions with which, in particular, a simple and economical feed of the sewed material layers to the sewing machine is possible without spoiling the sewing product, for example, by introduction of folds, whereby at least one feed device ( 5 ) is arranged between the supply device ( 3 ) and the sewing machine ( 2 ), along the entire feed length, lying on the material for sewing, which draws at least two sewed material layers from the supply device ( 13 ) and feeds the same into the sewing machine ( 2 ).

This invention relates to a multi-needle chain-stitch sewing machine for the production of mattress sheets, made from a sewing material comprising several, in particular at least three sewing material layers, preferably with one sewing material layer made from an elastic material, for example foamed material, and a cover layer with a sewing pattern, by means of a sewing unit and a supply device for the sewing material layers to be sewn.

Multi-needle chain-stitch sewing machines of this kind are known from prior art and usually include a sewing unit having a sewing material support with a pressure foot disposed above said sewing material support and a needle bar having arranged therein a plurality of needles. Below said sewing material support which is formed as a perforated plate said sewing machine includes shuttles in a number which particularly corresponds to the number of needles and which are attached to a shuttle bar. Said shuttles and needles are moved in an oscillating fashion in order to make chain stitches and double-chain stitches in the sewing material supported on said sewing material support. To this end, two threads, namely the upper thread fed to the needles and the under thread fed to the shuttles, are connected to each other. Multi-needle chain-stitch sewing machines of this type have been tried and tested particularly for the production of large-area sewing material in which several sewing material layers are interconnected. By means of such multi-needle chain-stitch sewing machines there are produced for example mattress sheets which as a rule are made from a cover layer, a non-tearing lower sewing material layer and an intermediate sewing material layer from an elastic material. A woven cloth or also a paper may serve as the non-tearing lower sewing material layer.

Within said sewing unit said sewing material layers are sewed together on one side and on the other side open or closed ornaments are sewed in said cover layer to give the mattress sheet an optically advantageous appearance.

In such multi-needle chain-stitch sewing machines the sewing material layers to be sewed together are kept at the ready in a supply device. From prior art it is known to have the sewing material layers to be sewed together stored in said supply device in the form of lap rolls, so that the same are withdrawn from said lap rolls in accordance with the progress of the sewing operation in the sewing unit. To this end stands are arranged in front of the sewing machine, having supported therein shafts which extend in a direction transversely of the sewing direction and each of which serving to receive one lap roll of said sewing material layers.

To be able to sew different patterns in different places of the sewing material the sewing material layers to be sewed together are usually arranged in a sewing material frame which is movable parallel to the needle bar or the shuttle bar and also in a feed direction in relation to the needles or the shuttles.

Such an arrangement as it has been tried and tested in prior art is already known from DE 196 10 979 C1. Ahead of the sewing unit a catwalk is arranged serving as a basis for a person monitoring the sewing operation. Under said catwalk the sewing material layers are passed over deflection rollers and are supplied thereafter to the sewing unit. The sewing material layers are supported on a stand and are withdrawn by means of driven rollers arranged upstream and downstream of the sewing unit. Therefore, the sewing material layers are permanently subject to tension.

A further form of a multi-needle chain-stitch sewing machine is known from U.S. Pat. No. 4,603,270 A1. In this multi-needle chain-stitch sewing machine four sewing material layers are provided in lap rolls and are sewed together in a sewing machine with a plurality of needles.

Finally, U.S. 6,170,414 B1 discloses a further multi-needle chain-stitch sewing machine for sewing together several sewing material layers which in turn are arranged in the form of lap rolls in a supply device where they are withdrawn from.

In all the above-described multi-needle chain-stitch sewing machines the withdrawal of the sewing material layers from the lap rolls over the entire distance from the lap rolls to the sewing unit takes place under tension, which fact is particularly disadvantageous for the middle one of the sewing material layers made from an elastic material, because in such an arrangement this sewing material layer is usually sewed under tension, so that the middle one of the sewing material layers will relax after the sewing unit and cause folds in the cover layer which is less elastic. This drawback is only avoided in the multi-needle chain-stitch sewing machine according to DE 196 10 979 C1.

In view of this prior art the invention is based on the problem of further developing a multi-needle chain-stitch sewing machine in a way such that the above-mentioned drawbacks of prior art are prevented by making it possible for the sewing material layers to be fed to the sewing machine in a particularly simple and inexpensive manner, without the result of the sewing operation being spoiled for example by the introduction of folds.

The solution of this problem provides that at least one feed device is arranged between the supply device and the sewing unit, which feed device rests against the sewing material along the entire feed distance and withdraws at least two sewing material layers from the supply device and feeds the same to the sewing unit.

According to the invention the multi-needle chain-stitch sewing machine includes a feed device that extends from the supply device to the sewing unit and rests against the sewing material layers along the entire feed distance between the supply device and the sewing unit, in order to feed the sewing material layers to the sewing unit with as less tension as possible, while any tension within the sewing material layers is avoided also in the section of the feed distance between the supply device and the sewing unit. Accordingly, the multi-needle chain-stitch sewing machine according to the present invention has a simple construction in the region of the feed distance and therefore allows the sewing material layers to be sewed together substantially without any tension in the sewing unit.

Preferably, the feed device is formed as a conveyor belt which rests on surfaces of the sewing material layer made from an elastic material and facing the cover layer of the sewing material, whereby the elastic material is frictionally conveyed. By this form of construction an advantage is obtained in particular that the elastic material which has a tendency to tension is not stretched within the feed distance and is thus fed to the sewing unit in a non-stretched condition. On the other hand, the additional sewing material layers have less tendency to stretch, so that the above-described problem occurs to a smaller extent.

In this form of construction a conveyor belt is provided that is arranged within the feed distance. In this form of construction the uppermost layer that is required for the feeding operation is formed by the second sewing material layer which for example consists of a non-tearing paper or woven cloth with limited extensibility which is constantly fed to the sewing machine and which may be kept under tension, without leading to the material being stretched.

A further development of the invention provides that that feed device consists of two conveyor belts which are arranged on opposite sides and extend parallel and between which the sewing material or the sewing material layers are conveyable. This form of construction particularly offers an advantage that the conveying of the sewing material layers may be effected much more accurately between two conveyor belts, so that possible extensions particularly in the elastic material may be further reduced. In addition, such a construction has the advantage that the start-up of the multi-needle chain-stitch sewing machine with fresh sewing material layers is considerably simplified, because any complicated introduction of the non-tearing and non-stretching sewing material layer is not necessary to an extent that the feed device automatically takes up and conveys sewing material layers that are fed together.

The sewing material is arranged to be movable in relation to the sewing unit in a direction extending transversely with respect to the feeding direction of the sewing material. To this end it is preferably provided that the sewing material is guided on a conveyor carriage which is movable transversely with respect to the sewing material feeding direction. On the other hand, the needle and shuttle bars are fixed. By the relative movement of the sewing material with respect to the sewing unit the variability of the patterns that may be sewed is considerably increased. The feed length which is arranged upstream of the sewing unit and the supply device which is connected to the feed length are movable together with the sewing material support.

According to a further feature of the invention it is provided that the supply device includes a conveyor belt where for example at least the lowermost sewing material layer and the sewing material layer made from an elastic material may be placed on in the form of a lap roll, with said lap rolls being fixedly supported in brackets to be fixed against any translational movement in the direction of the conveyor belt.

Consequently, said supply device includes a conveyor belt. The sewing material layers are placed on this conveyor belt in the form of lap rolls and are fixed against any translational movements in the conveying direction. With this construction the withdrawal of the sewing material layers from the lap rolls is not effected under tension but through frictional connection between the conveyor belt and the sewing material layer. This too, contributes to substantially avoid stretching at least of the sewing material layer made from an elastic material.

In order to be able to follow the movements of the sewing material in the sewing unit transversely with respect to the conveying direction and particularly to avoid any shearing strain within the sewing material it is provided that the conveyor belt is arranged in a frame which is arranged for displacement in a direction extending at right angles to the conveying direction of the sewing material. The displacement of the frame is synchronized with the displacement of the sewing material in relation to the sewing unit.

Finally, according to a further feature of the invention it is provided that the conveyor belt of the supply device is extended up to the conveyor belt, by means of which the sewing material may be fed to the sewing unit. Accordingly, the conveyor belts in the feed distances between the sewing machine and the supply device on one side and within the supply device on the other side are formed separately, which fact particularly simplifies the handling of the multi-needle chain-stitch sewing machine, since long lengths of conveyor belts and problems inherent to them like slippage and incorrect conveying are avoided. In contrast thereto, a transfer station between two conveyor belts can be handled much easier. In addition, this configuration leads to the advantage that the structure of such a multi-needle chain-stitch sewing machine is substantially simplified. At the same time it is possible to mechanically uncouple the conveyor belt lengths, so that for example a purely electronic coupling of the movements of the conveyor belts in the conveying direction and in the opposite direction as well as transversely with respect to the conveying direction is readily possible.

Moreover, the above-described multi-needle chain-stitch sewing machine has the advantage that compared to prior art a smooth reverse motion of the sewing material in relation to the original conveyor device is possible, since by the configuration of the multi-needle chain-stitch sewing machine with the conveyor devices that almost fully rest against the sewing material layers over the entire feed distance the capability of reversing the sewing material conveying direction is considerably improved by the sewing material being kept under a constantly low tension also during the reverse motion of the conveyor devices, which is required for performing particular sewing operations.

Further features and advantages of the present invention will become apparent from the following description of the attached drawings showing a preferred embodiment of the multi-needle chain-stitch sewing machine according to the present invention. In the drawings it is shown by:

FIG. 1 a multi-needle chain-stitch sewing machine with an upstream supply device and a downstream winding station in a lateral view;

FIG. 2 the multi-needle chain-stitch sewing machine with the upstream supply device and the downstream winding station in a top view;

FIG. 3 a conveyor device arranged upstream of a sewing unit of the multi-needle chain-stitch sewing machine, in a partly sectional side view; and

FIG. 4 the supply device according to FIG. 1 in a detailed side view.

In FIG. 1 a multi-needle chain-stitch sewing machine 1 is shown in a side view. This multi-needle chain-stitch sewing machine 1 comprises a sewing unit 2 and a supply device 3 having arranged therein lap rolls 4 of the sewing material layers 17, 19 to be sewed together in sewing unit 2.

Between the supply device 3 and the sewing unit 2 a feed device 5 is arranged through which at least a part of the sewing material layers 17, 19 is fed to the sewing unit 2.

The sewing material layers withdrawn from the sewing unit 2 and sewed together are shown as sewed material 6 in FIG. 1. The multi-needle chain-stitch sewing machine 1 has a downstream winding station 7 in which the finished sewed material 6 is wound up.

Furthermore, the multi-needle chain-stitch sewing machine 1 comprises a thread supply device 8 which is arranged between the conveyor device 5 and the supply device 3 and includes a cantilever arm 9 which reaches up and into the zone above the sewing unit 2, in order to feed the thread to be withdrawn to the sewing unit 2.

The conveyor device 5 is shown in greater detail in FIG. 3 and consists of a first conveyor belt 10 which continuously moves over a plurality of deflection rollers 11 and further over a driving roller 12 which is driven via a belt 13 which is positively and/or non-positively driven by a driving motor not further shown. The deflection rollers 11 and the driving roller 12 of the conveyor belt 10 are arranged in the lower region of the conveyor device 5 and have a wrapping angle of partly more than 180° of the individual deflection rollers 11 and the driving roller 12.

In the upper region of the conveyor device 5 the conveyor belt 10 is passed over a baffle plate 14, of which the end 15 is formed with a pointed cross section in the direction of the sewing unit 2.

Further, in the conveyor device 5 a second conveyor belt 16 is provided which is arranged to extend in parallel with the first conveyor belt 10 in the region of the feed length for the sewing material layers 17, particularly those made from an elastic material. The spacing between the two conveyor belts 10 and 16 is variable corresponding to the sewing material layers 17 to be conveyed, so that sewing material layers 17 of a greater thickness may be conveyed as well without any considerable compression parallel to the surface normal of the sewing material layers 17.

The transport direction of the conveyor belt 10 is shown by means of an arrow 18 on a lower deflection roller 11, with both conveyor belts 10 and 16 being driven in a reversible fashion, in order to feed the sewing material layer 17 towards or away from the sewing unit 2, depending on the sewing pattern that has to be produced.

The sewing material layer 17 illustrated in FIG. 3 consists of a lower layer of non-tearing paper not further shown and of a sewing material layer 17 made from an elastic material, namely a foamed material, on top of it. These two layers are fed to the sewing unit 2 together with a sewing material layer 19 which is also tension- or tearing-resistant and is formed as a cover layer. The sewing material layer 19 is stored in a lap roll not further shown in the region of the feed device 5 and is fed to the sewing unit 2 via a deflection roller 20 and a driving roller 21 driven by the belt 13, said sewing material layer 19 being placed onto the sewing material layer 17 directly after the end 15.

Finally, in FIG. 3 a third conveyor belt 22 is shown which is assigned to the supply device 3 and which will be described in the following.

The feed device of the sewing material layers 17, 19 is shown in FIG. 3 by means of arrow 23, the entire feed device 5 being supported in the multi-needle chain-stitch sewing machine 1 for limited displacement at right angles with respect to the conveying direction of the sewing material layers 17, 19, in order to be capable of performing also closed, circular or similar sewing patterns in the sewing material layer 19 and accordingly also in the sewing material layer 17.

The supply device 3 is shown in detail in FIG. 4 and includes the conveyor belt 22 already mentioned above, which is arranged within a frame 24 (FIG. 2) that is supported on rails 25 extending transversely with respect to the conveying direction of the conveyor belt 2 and is movable along these rails 25 transversely with respect to the conveying direction of the conveyor belt 22, said capability of displacement being limited corresponding to the capability of transverse displacement of the feed device 5.

The conveyor belt 22 is driven by means of a driving motor 26, of which the running direction may be reversed, so that the conveyor belt 22, too is reversible.

On its rear end associated with the driving motor 26 the frame 24 includes a support 27 for receiving the first lap roll 4 with the first tearing- or tension-resistant sewing material layer, with said layer consisting for example of non-tearing paper or a woven fabric which has only a low coefficient of extension and with said lap roll directly resting on the conveyor belt 22 by the outer surface area thereof. The first sewing material layer withdrawn from this lap roll fully rests on the conveyor belt 22 and extends through the conveyor device 5 at least up to the sewing unit.

The supply device 3 further includes a transport and handling device 28 which is formed as a portal frame 29 arranged above frame 24. This portal frame 29 includes four perpendicularly aligned posts 30 and two horizontally aligned longitudinal supports 31, each of which interconnecting two posts 30, said longitudinal supports 31 being arranged to extend parallel to each other and parallel to the conveying direction of the conveyor belt 22 and being interconnected by means of cross members 32.

The portal frame 29 is anchored to the floor 33 and has a width between the longitudinal supports 31 which is larger than the width of the frame 24, so that this frame 24 may be displaced within the portal frame 25 corresponding to the above description at right angles to the conveying direction.

Furthermore, the longitudinal supports 31 in the portal frame 29 have provided thereon lifting means 34 which consist of cross members 35 that may be displaced in the portal frame 29 in a direction transversely with respect to the conveying direction of the conveyor belt 22, on which cross members grippers 39 may be lowered through Bowden cables not further shown. The grippers 39 include a web extending parallel to the cross members 35 and on the ends thereof legs 36 that extend at right angles to the web and that carry on the free ends thereof hook members not further shown for receiving a shaft 38 passing through the respective lap roll 4 of the sewing material layer 17.

In the region of the frame 24 a guiding device 37 is arranged for each lap roll 24 in which the respective lap roll 4 of the sewing material layer 17 may be placed. Such a guiding device 37 makes it possible for the lap roll 4 to be placed on the conveyor belt 2 by the outer surface area thereof 2 or on the first sewing material layer of the first lap roll 4 already supported thereon.

The guiding device 37 may be configured so that on both sides of the conveyor belt 22 a web with a perpendicularly extending slot for receiving shaft 28 is arranged, with the shaft 38 being guided for rotation within said slot, so that the sewing material layer may be withdrawn from the lap roll 4 over the conveyor belt 22, while any translational movement of the lap roll 4 is avoided.

As an alternative, the guiding device 37 may consist of mutually spaced guide members overlapping the conveyor belt 22 and serving to receive the lap roll 4 and including guide rollers abutting the outer surface area of the lap roll 4 for guiding the sewing material layers during withdrawal thereof with as less friction as possible.

The handling of the above-described transport and handling device 28 is as follows:

A lap roll 24 is provided in the zone laterally of the portal frame 29 and is fitted with the shaft 38 (FIG. 2) which passes through the center of the lap roll 4.

Thereafter, the cross member 35 is moved out and the U-shaped gripper 39 (FIG. 4) lowered by the lifting device 34, until the legs 36 of the gripper 39 may be connected to the shaft 38 by means of hook members not further shown. Then the lap roll 4 is lifted and the cross member 35 moved back into the portal frame 29 in a manner such that the lap roll 4 is arranged above a further lap roll 4 just being processed. After the use-up of the lap roll 4 just being processed the lap roll 4 arranged above said used-up lap roll 4 may be lowered within a very short time and the sewing material layer 17 withdrawn from it forwarded to the working process. After the lowering of the lap roll 4 the above-described operation is repeated, i.e. a further lap roll 4 stored above the lap roll 4 just being processed.

The same of course applies to all lap rolls 4 illustrated in FIG. 4.

The sewing material layers 17 withdrawn from the lap rolls 4 rest on the conveyor belt 22 and are conveyed to the region of the two conveyor belts 10 and 16 which take up and feed the end of the sewing material layers 17 in the direction of the sewing unit 2. A short distance ahead of the sewing unit 2 the sewing material layers 17 thus conveyed are united with the cover layer 19 and together are fed to the sewing unit 2 for being sewed together.

The construction of the multi-needle chain-stitch sewing machine of the invention according to the above-described embodiment makes it possible for the sewing material layers 17, 19 to be fed almost in a non-stretched condition, and at the same time the sewing process is simplified, because the sewing material layers 17,19 may be conveyed both in a direction transversely with respect to the normal sewing direction and in the normal sewing direction and also in a reversed sewing direction, without the sewing material layers 17, 19 being extended or upset. To this end it is provided that the conveyor belts 10, 16 and 22 are electronically interconnected in such manner that the conveying directions of all the conveyer belts 10, 16, 22 are coordinated with each other. The same also applies to the driving roller 21 feeding the cover layer 19 to the sewing unit 2. In addition to the conveyor belts 10, 16 and 22 also the cross displacement devices of the feed device 5 and of the frame 24 of the supply device 3 are electronically interconnected.

The invention is not limited to the above-described embodiment. Various changes and modifications are possible within the scope of the present invention. For example, the conveyor device 5 may also have only the conveyor belt 10. In such a case the lowermost sewing material layer forms the abutment for the conveying of the central sewing material layer 17 made from an elastic material. In addition, at least one of the illustrated conveyor belts 10, 16, 22 may be formed by a plurality of mutually aligned juxtaposed rollers which also rest against the sewing material layers 17 and which serve to convey said sewing material layers 17. 

1. Multi-needle chain-stitch sewing machine for the production of mattress sheets, made from a sewing material, comprising several, in particular at least three sewing material layers, preferably with one sewing material layer made from an elastic material, for example foamed material, and a cover layer with a sewing pattern, with a sewing unit and a supply device for the sewing material layers to be sewn, characterized in that between said supply device (3) and said sewing unit (2) at least one feed device (5) is arranged which rests against the sewing material over the whole feed length between the supply device (3) and the sewing unit (2), said feed device withdrawing at least two sewing material layers from the supply device (3) and feeding the same up and into the sewing unit (2).
 2. Multi-needle chain-stitch sewing machine according to claim 1, characterized in that the feed device (5) is formed as a conveyor belt (10) which rests on the surface of the sewing material layer (17) made from an elastic material which faces the cover sheet (19) of the sewing material.
 3. Multi-needle chain-stitch sewing machine according to claim 1, characterized in that the feed device (5) consists of two conveyor belts (10, 16) which are arranged oppositely and parallel to each other and between which the sewing material is conveyable.
 4. Multi-needle chain-stitch sewing machine according to claim 1, characterized in that the sewing material is movable in relation to the sewing unit (2) in a direction transversely with respect to the conveying direction of the sewing material.
 5. Multi-needle chain-stitch sewing machine according to claim 1, characterized in that the supply device (3) includes a continuous feed device, by means of which the sewing material layers, in particular at least the lowermost sewing material layer and the sewing material layer (17) made from an elastic material are conveyable in the direction of the sewing unit (2).
 6. Multi-needle chain-stitch sewing machine according to claim 5, characterized in that the feed device is formed as a conveyor belt (22), by means of which the sewing material layers are conveyable in the direction of the sewing unit (2).
 7. Multi-needle chain-stitch sewing machine according to claim 6, characterized in that the conveyor belt (22) is arranged in a frame (24) which is arranged for displacement in a direction extending at right angles to the conveying direction of the sewing material layers (17).
 8. Multi-needle chain-stitch sewing machine according to claim 7, characterized in that the displacement of the frame (24) is synchronized with the displacement of the sewing material in the feed device (5) in relation to the sewing unit (2).
 9. Multi-needle chain-stitch sewing machine according to claim 6, characterized in that the conveyor belt (22) of the supply device (3) is extended up to the conveyor belt (10), by means of which the sewing material may be fed to the sewing unit (2).
 10. Multi-needle chain-stitch sewing machine according to claim 5, characterized in that the sewing material layers may be placed on the feed device (5) in the form of lap rolls (4) in such a manner that the sewing material layers are taken up by the conveyor device and conveyed to the sewing unit.
 11. Multi-needle chain-stitch sewing machine according to claim 10, characterized in that the lap rolls (4) are supported in brackets in a manner to be fixed against any translational movement in the conveying direction of the conveyor device.
 12. Multi-needle chain-stitch sewing machine according to claim 6, characterized in that the sewing material layers may be laid on in the form of lap rolls (4), with said lap rolls (4) being supported in brackets in a manner fixed against any translational movement in the conveying direction of the conveyor belt (22).
 13. Multi-needle chain-stitch sewing machine according to claim 5, characterized in that the feed device of the supply device (3) is extended up and into the zone of a conveyor device (10), by means of which the sewing material may be fed to the sewing unit (2).
 14. Multi-needle chain-stitch sewing machine according to claim 13, characterized in that the transport and handling device (28) consists of a stand (30) having arranged therein one cross member (35) for each lap roll (4), said cross members each including a lifting device (34) for lifting and lowering a lap roll (4).
 15. Multi-needle chain-stitch sewing machine according to claim 14, characterized in that said cross members (35) are aligned transversely with respect to the conveying direction of the supply device (3) and are preferably supported for displacement in relation to the stand (30).
 16. Multi-needle chain-stitch sewing machine according to claim 14, characterized in that the lifting device (34) consists of a U-shaped gripper (39) with two legs (36) arranged on a web, which legs comprise hook members for receiving a shaft (38). 